Apparatus for preforming at least a portion of a material

ABSTRACT

Apparatus and methods of stretch-forming pre-preg material are provided. In one example embodiment, a variable material stretch-forming apparatus comprises a stretch-forming assembly configured to stretch-form at least one section of a sheet of pre-preg material to a longer length than at least one other section of the sheet of pre-preg material before the sheet of pre-preg material is applied to a tool.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/832,251, filed Jul. 8, 2010, now U.S. Pat. No. 9,266,279, issued Feb.23, 2016, the disclosure of which is hereby incorporated herein in itsentirety by this reference.

BACKGROUND

Pre-impregnated (pre-preg) material is used in the formation ofhigh-strength low weight structures, such as, but not limited to, partsused to build aircraft and spacecraft. Pre-preg material is typicallymade-up of a composite of reinforcing fibers (such as carbon, glass,aramid, and the like) that are bonded together with a resin system.Pre-preg material is typically manufactured in flat sheets that areapplied in multiple fiber orientation layers onto surfaces of a tool toform the shape of a desired part. The laminate is subsequently compactedand heat set (cured or fused) into a composite structure. Other methodsof hardening or curing the laminate can also be used with some resinsincluding, but not limited to, electron beam cure, microwave cure andultraviolet light cure. There are various pre-preg materials fiberarchitectures that include, but are not limited to, woven fabric,unidirectional tape (uni-tape), non-crimp stitched broadgoods, braid,multi-dimensional weave, stretch broken fibers, and strategicallystitched materials. A wide variety of resins can be used including, butnot limited to, room temperature set resins, thermoset resins, andthermoplastic resins. The application of pre-preg material on tools,which have forming surfaces with at least two different radii ofcurvature, can be difficult to accomplish without wrinkling thematerial, folding the material, or requiring the fibers to be cut(darting the material to conform without creating folds or wrinkles);all of which generally reduces structural properties and functionalityof the structure.

For the reasons stated above and for other reasons stated below thatwill become apparent to those skilled in the art upon reading andunderstanding the present specification, there is a need in the art fora method of conditioning or stretch-forming pre-preg material foreffective and efficient application to forming surfaces of a tool havingat least two different radii of curvature.

SUMMARY

The above-mentioned problems of current systems are addressed byembodiments of the present disclosure and will be understood by readingand studying the following specification. The following summary is madeby way of example and not by way of limitation. It is merely provided toaid the reader in understanding some of the aspects of the disclosure.Although, only a structure is described in the summary, methods are alsoclaimed and described in the application.

In one embodiment, a variable material stretch-forming apparatus isprovided. The variable material stretching apparatus comprises astretch-forming assembly configured to stretch-form at least one sectionalong a width of a sheet of pre-preg material to a longer length than atleast one other section along the width of the sheet of pre-pregmaterial before the sheet of pre-preg material is applied to a tool.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present disclosure can be more easily understood and furtheradvantages and uses thereof more readily apparent, when considered inview of the detailed description and the following figures in which:

FIG. 1 is a top view example illustration of an off-axis pre-pregmaterial used in embodiments of the present disclosure;

FIG. 2 is a partial side perspective view of a tool having at least twodifferent radii of curvature;

FIG. 3 is a side perspective view of a stretch-forming assembly of oneembodiment of the present disclosure;

FIG. 4 is a block diagram of a stretch-forming assembly of oneembodiment of the present disclosure;

FIG. 5 is a side perspective view of a stretch-forming device of oneembodiment of the present disclosure;

FIG. 6 is a side perspective view of another embodiment of astretch-forming device of the present disclosure;

FIG. 7A is an assembled side view of a stretch-forming device of anotherembodiment of the present disclosure;

FIG. 7B is a close-up view of a section of a belt of the stretch-formingdevice of FIG. 7A;

FIG. 7C is a partially unassembled side view of the stretch-formingdevice of FIG. 7A;

FIG. 8 is a cross-sectional side perspective view of yet anotherembodiment of a stretch-forming device of the present disclosure;

FIG. 9 is a side perspective view of a composite structure formingassembly using a roll of material prepared with one embodiment of thepresent disclosure;

FIG. 10 is a side perspective view of a composite structure formingassembly incorporating a pre-preg stretch-forming assembly, in-line witha roll of unstretched material in one embodiment of the presentdisclosure;

FIG. 11A is a side perspective view of a stretch-forming assembly and aroll storage of an embodiment of the present disclosure;

FIG. 11B is a side perspective view of an embodiment of thestretch-forming assembly of FIG. 11A;

FIG. 12A is a side perspective view of a shaped-core and nip rollers ofa stretch-forming assembly of another embodiment of the presentdisclosure;

FIG. 12B is a side perspective view of a stretch-forming assembly with ashaped core of another embodiment of the present disclosure;

FIG. 13 is a side perspective view of the shaped-core of thestretch-forming assembly of FIG. 12A with at least one layer ofstretch-formed material used in another embodiment of the presentdisclosure;

FIG. 14 is a side perspective view of the shape-core of FIG. 12A withtransverse forming rollers of one embodiment of the present disclosure;

FIG. 15 is a side perspective view of the shape-core of FIG. 12A with aforming track of one embodiment of the present disclosure;

FIG. 16 is a side perspective view of the shaped-core of FIG. 12A with aforming gear of one embodiment of the present disclosure; and

FIG. 17 is a forming flow diagram of one embodiment of the presentdisclosure.

In accordance with common practice, the various described features arenot drawn to scale but are drawn to emphasize specific features relevantto the present disclosure. Reference characters denote like elementsthroughout the figures and the text.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the disclosure maybe practiced. These embodiments are described in sufficient detail toenable those skilled in the art to practice the disclosure, and it is tobe understood that other embodiments may be utilized and that changesmay be made without departing from the spirit and scope of the presentdisclosure. The following detailed description is, therefore, not to betaken in a limiting sense, and the scope of the present disclosure isdefined only by the claims and equivalents thereof.

When flat sheets of pre-preg material are formed into a radial patternthey must be stretched in length as they conform to an increasingradius. This is typically done by hand on a tool surface as material ispressed into place and stretched manually from a smaller radius to alarger radius. Embodiments of the present disclosure create a method ofdoing this stretching automatically, prior to touching the tool surface.In embodiments, pre-preg material is stretch-formed before laying thematerial onto the tool surface. This increases the speed at which thematerial can be formed onto the tool thereby reducing labor content inthe lay-up process and improving consistency of the forming by runningthe material through a machine operation instead of stretching itmanually. In an embodiment, specific sections along a width of a sheetof pre-preg material are pre-formed by stretching the specific sectionsso they will travel a longer path distance on a forming surface of atool. For a section of material to travel a longer path distancerelative to another section of material, it must increase its lengthwisedimension or stretch. There is typically little or no elastic behaviorin the longitudinal direction of continuous fibers of the pre-pregmaterial. Generally, stretch of the material comes from stretching theresin matrix that holds the fibers together and spreading the fiberbundles transverse to their longitudinal direction. With off-axismaterials, the angle orientation of the fibers can change and thematerial can reduce in fiber area density to achieve the lengthwisedimensional increase. There may be a corresponding narrowing of widthdimension in the stretch section in some embodiments. Examples ofpre-preg material that can have sections stretched include, but are notlimited to, woven fabrics, off-axis unidirectional tapes, non-crimpstitched broadgoods, braids, multi-dimensional weaves, stretch brokenfiber products (off-axis and uni-directional) and strategically stitchedmaterials.

FIG. 1 illustrates a sheet of off-axis pre-preg material 100. Inparticular, in this example the pre-preg material 100 is uni-tape havingspaced fibers 102 that are at a select orientation angle 106 in relationto an edge 108 of the sheet 100 (i.e., the orientation of the fibers 102are off-axis in relation to the edge 108). The fibers 102 arepre-impregnated with, and held together by, resin 104. FIG. 2illustrates a portion of a tool 200 that has tool surfaces having atleast two different radii of curvature. In particular, tool 200 includesa forming surface 202, which can generally be referred to herein as a“web” or “cylinder” of the tool. In the example in FIG. 2, the tool 200has a constant radius from its center of revolution. Extending from web202 are forming surfaces 204 and 206, which both can be generallyreferred to as “flanges,” “tool flanges,” or “turned up flanges.”Flanges 204 and 206 can have the same or different outer radii ofcurvature necessitating the same or different amounts of linear stretchof pre-preg material to conform to the surfaces. Referring to flange206, flange 206 has a first radius of curvature R1 and a seconddifferent radius of curvature R2. R2 has a greater radius of curvaturethan R1. In applying a sheet of pre-preg material (such as the off-axispre-preg material 100) on the forming surfaces 202, 204, 206 of the tool200, the pre-preg material 100 must be pressed to extend about flanges204, 206 of the forming tool. However, even initially applying thepre-preg material 100 to the tool 200 can be a challenge since the shapeof the forming surfaces 202, 204, 206 in relation to each other does notlend to the application of a flat sheet of pre-preg material 100 in aconformal manner. Further, it is difficult to get the sheet of pre-pregmaterial 100 to lie on the forming surfaces 202, 204, 206 of the tool200 in a desired fashion because of the differences of curvature of theradiuses of R1 and R2 of the tool 200 illustrated in FIG. 2. Moreover,pre-preg material 100 that conforms to surface 202 will not conform tosurfaces 204 or 206 without stretching or darting to meet the increasedradius R2.

Referring to FIG. 3, a side perspective view of a stretch-formingassembly 300 of one embodiment is illustrated. The stretching assembly300 takes the pre-preg material 100 and stretches select sections alonga width of the pre-preg material 308 and 306 so that an increase incurvature of radius on a forming surface, such as R2 in relation to R1can be accommodated. In particular, FIG. 3 illustrates a pre-formedpre-preg material 302 that includes a first section 304 that has notbeen stretched and sections 306 and 308 that have been stretched toaccommodate different radius of curvature, such as the different radiusof curvatures present in the forming surfaces 204 and 206 of tool 200illustrated in FIG. 2. Although FIG. 3 illustrates an embodiment wheretwo sections 306 and 308 of a preformed pre-preg material 302 have beenstretched, any number of sections of a pre-formed pre-preg material 302could be stretched depending on a particular shape of the formingsurfaces of a tool. Moreover, the stretching may also occur for a selectdistance along the length of the material.

FIG. 4 illustrates a block diagram of a stretch-forming assembly 400. Inparticular, FIG. 4 illustrates a stretch-forming device 402 (embodimentsof which are further described below), a motor or motors 404 and astretch-forming controller 406. The controller 406 controls the motor ormotors 404 to activate the shaping device 402. In one embodiment, thestretch-forming controller 406 is in communication with an assemblycontroller 408 that allows synchronization between the stretch-formingdevice 402 and an assembly 410. Examples of assemblies 410 that could besynchronized with the stretch-forming device 402 are the formingassembly 1000 of FIG. 10 and the storage core 1120 of FIGS. 11A and 11B,each of which is described in further detail below. In FIG. 5, anexample stretch-forming device 500 of one embodiment is illustrated. Inparticular, FIG. 5 is a side perspective view of a rollerstretch-forming device 500. The roller stretch-forming device 500includes a first roller 502 and a second roller 504. The first roller502 is positioned adjacent the second roller 502 such that a surface ofthe first roller 502 engages a surface of the second roller 504. Inparticular, the first roller 502 and the second roller 504 arepositioned so that a sheet of pre-preg material can pass between thefirst roller 502 and the second roller 504, as the first and secondroller 502 and 504 rotate. In the embodiment of FIG. 5, the first roller502 includes a first cylindrical shaped roller section 502 a and asecond conical roller section 502 b. The second roller 504 similarlyincludes a first cylindrical roller section 504 a and a second conicalroller section 504 b. The first cylindrical roller section 504 a of thesecond roller 504 engages the first cylindrical roller section 502 a ofthe first roller 502. The second conical shaped section 504 b of thesecond roller 504 engages the second conical shaped section 502 b of thefirst roller 502.

In the embodiment of FIG. 5, the second conical section 502 b of thefirst roller 502 includes a first end 501 b and a second end 501 c. Thefirst end 501 b of the second conical section 502 b abuts a first end501 a of the first cylindrical section 502 a. The diameter of the firstcylindrical section 502 a of the first roller 502 is approximately equalto the diameter at the first end 501 b of the second conical section 502b of the first roller 502. The second end 501 c of the second conicalsection 502 b of the first roller 502 has a greater diameter than thefirst end 501 b of the second conical section 502 b of the first roller502. The second conical section 504 b of the second roller 504 includesa first end 503 b and second end 503 c. The first end 503 b of thesecond conical section 504 b of the second roller 504 is positionedadjacent a first end 503 a of the first cylindrical section 504 a of thesecond roller 504. The first end 503 b of the second conical section 504b of the second roller 504 has a diameter approximately equal to thediameter of the first cylindrical section 504 a of the second roller504. The second end 503 c of the second conical section 504 b of thesecond roller 504 has a smaller diameter than the first end 503 b of theconical section 504 b of the second roller 504. Hence, the shape of thesecond conical section 504 b of the second roller 504 conforms to theshape of the second conical section 502 b of the first roller 502. Inthe embodiment of FIG. 5, a section of pre-preg material that passesbetween the second conical sections 502 b of the first roller 502 andthe second conical section 504 b of the second roller 504 is stretchedin relation to a remaining section of pre-preg material passing betweenthe first cylindrical section 502 a of the first roller 502 and thefirst cylindrical section 504 a of the second roller 504. Hence, in thisembodiment only one section of pre-prep material is stretched. In oneembodiment, the second conical section 504 b of the second roller 504 issegmented into segments 506-1 through 506-n, as illustrated in FIG. 5.Further, in one embodiment each of the segments 506-1 through 506-n isdesigned to move independently of each other such that differentrotational speeds in different segments 506-1 through 506-n can beachieved. This further enhances stretching of the material between thesecond conical sections 502 b and 504 b. An embodiment, furtherillustrating independent moving segments of a roller is provided belowin regard to FIG. 8. Roller 502 is driven by a motor, such as motor 404illustrated in FIG. 4. Rollers 504, in one embodiment, are not drivenand are free to rotate at speeds related to geometry of rollers 502.Further, some embodiments apply a back tension on the pre-preg materialas the stretch-forming device 500 selectively stretches sections of thepre-preg material to help prevent steering issues that can occur whenthe pre-preg material passes through the stretch-forming device 500.Examples of assemblies that can apply the back tension are the supplyroll-off 1130 of FIGS. 11A and 11B and the nip rollers 1220 and 1222 ofFIG. 12A, which are further described in detail below.

Referring to FIG. 6, another embodiment of a stretch-forming device 600is illustrated. In particular, FIG. 6 illustrates a gear stretch-formingdevice 600. The gear stretch-forming device 600 includes a cylindricallyshaped first roller 602 and cylindrically shaped second roller 604(i.e., a pair of mating rollers 602 and 604). The first roller 602includes a first gearing end 602 a and a second gearing end 602 b. Thesecond roller 604 also includes a first gearing end 604 a and a secondgearing end 604 b. Each gearing end 602 a and 602 b of the first roller602 and each gearing end 604 a and 604 b of the second roller 604,respectively, includes a plurality of rounded teeth 220 (or shaped gearteeth) separated by a plurality of grooves 222. In one embodiment, theteeth 220 are shaped irregularities similar to shaped gear teeth. Asillustrated in FIG. 6, the gearing of the first roller 602 is mated withthe gearing of the second roller 604. In particular, teeth 220 of gearend 602 a of the first roller 602 are received in grooves 222 of gearend 604 a of the second roller 604 and teeth 220 of the first gear end604 a of the second roller 604 are received in grooves 222 of the firstgear end 602 a of the first roller 602. Likewise, teeth 220 of thesecond gear end 602 b of the first roller 602 are received in grooves222 of the second roller 604 and teeth 220 of the second gear end 604 bof the second roller 604 are received in grooves 222 of the second gearend 602 b of the first roller 602. In this embodiment, as a sheet ofpre-preg material passes between the first and second rollers 602 and604 the respective gear ends 602 a and 604 a of the first and the secondrollers 602 and 604 stretch a first end section of the pre-pregmaterial. The second roller ends 602 b and 604 b of the first and secondrollers 602 and 604 stretch a second section of the pre-preg material.Hence, in this embodiment two different sections of pre-preg materialare stretched with the gear stretching device 600. Both gears for firstroller 602 and second roller 604 are motor driven to maintainsynchronized mating of teeth 220 and valleys 222 in one embodiment. Inone embodiment, teeth 220 and valleys 222 do not physically contact soas to allow the pre-preg material to move freely widthwise as it isstretched in the lengthwise direction moving through the convoluted pathcreated by teeth 220 and valleys 222. In another embodiment, thepre-preg material is gripped along the entire length of the constantcross-section, and along a contact line in the geared sections.Moreover, in another embodiment, the distance between the teeth 220 andvalleys 222 of opposed rollers 602 and 604 are adjustable.

FIGS. 7A-7C illustrate yet another embodiment of a stretch-formingdevice 700. In particular, FIGS. 7A and 7C illustrate a beltstretch-forming device 700. FIG. 7A illustrates an assembled beltstretch-forming device 700 and FIG. 7C illustrates the beltstretch-forming device 700 partially unassembled. The beltstretch-forming device 700 includes a first belt member 701 and secondbelt member 703. The first belt member 701 and the second belt member703 are positioned to pass a sheet of pre-preg material 720 betweenthemselves, as illustrated in FIG. 7A. The first belt member 701includes an endlessly looped belt 702 and an endlessly looped stretchingbelt 704. Belt 702 and stretching belt 704 are engaged with rotatingsupport drums 710 and 712. The second belt member 703 includes anendless looped belt 706 and an endlessly looped stretching belt 708.Belt 706 and stretching belt 708 are engaged with rotating support drums714 and 716, respectively. The close-up view 750 of FIG. 7A illustratesthat in one embodiment, the belts 702 and 706 include spikes 752. Thespikes 752 are designed to firmly grab the pre-preg material 702, whilenot harming the pre-preg material 702. Referring to FIG. 7C, therotating support drums 710 and 712, engaged to the first belt member701, are segmented into rotating support drum sections 710 a and 710 band rotating support drum sections 712 a and 712 b. Belt 702 engagesrotating support drums sections 710 a and 712 a, respectively.Stretching belt 704 is engaged to rotating support drums 710 b and 712b, respectively. Stretching belts 704 and 708 each include a pluralityof fins 711 (or ribs). The fins 711 are used to stretch a section of thesheet of pre-preg material 720. Referring back to FIG. 7A, the fins 711on the stretching belt 704 and 708 are positioned so they stagger eachother as the sheet of pre-preg material 720 is pulled between the firstbelt member 701 and the second belt member 703 as the first and secondbelt members 701 and 703 are rotated. As FIG. 7B illustrates, the fins711 of the stretching belts 704 and 708, stretch a section 720 a of thesheet of pre-preg material 720. Hence, as the sheet of pre-preg material720 is moved between the first belt member 701 and the second beltmember 703 of the belt stretching device 700, section 720 a of the sheetof pre-preg material 720 is stretched by the fins 711. Furtherillustrated in FIGS. 7A and 7C, a first pressure platen 730 ispositioned within stretching belt 704 and a second pressure platen 732is positioned in stretching belt 708. The pressure platens 730 and 732apply pressure on the respective stretching belts 704 and 708 to stretchthe pre-preg material 720. In embodiments, the pressure platens 730 and732 are adjustable so that the amount of pressure can be selected. Alsoillustrated in FIG. 7C, is a third pressure platen 734 designed to applypressure to belt 702. A similar pressure platen is designed to applypressure to belt 706. Pressure platen 734 is also adjustable, in oneembodiment. In another embodiment, belts 702 and 704 of the first beltmember 701 are integral as one unit with rollers 710 a, 710 b and 712 a,712 b of the first belt member 701 also being integral as one unit.Similarly, the second belt member 703, in one embodiment, is integral asone unit. In yet other embodiments, more than two belt and rollerassemblies per set are used with more complex forming work.

Yet still another embodiment of a stretch-forming device 800 isillustrated in FIG. 8. In particular, FIG. 8 illustrates a segmentedroller stretch-forming device 800. This embodiment includes a firstdrive system 810 that is attached to a shaft system 802. The drivesystem 810 is shown as using gears, but could be driven by other means.The drive system 810 includes gears 810 a through 810 g that arecoupled, respectively, to shafts 802 a through 802 g of the shaft system802. Shafts 802 a though 802 g are, in turn, attached to segmenteddriven rollers 812 a through 812 g. The segmented driven rollers 812 athrough 812 g are in contact with segmented non-driven rollers 814 athrough 814 g. The non-driven rollers 814 a through 814 g arerotationally mounted on shaft 818. A sheet of pre-preg material 816 ispassed between the driven rollers 812 a through 812 g and the respectivenon-driven rollers 814 a through 814 g. In the embodiment of FIG. 8,gears 810 a through 810 g are driven by individual motors via gear teeth811 that drive each respective roller 812 a through 812 g at individualspeeds to control an amount of pre-preg stretch in those correspondingregions. For example, roller 812 a could be driven at a rotational speedthat is different than the rotational speed at which roller 812 b isdriven, which, in turn, could be different than the rotational speed atwhich roller 812 c is driven, and so-forth. This allows a sheet ofpre-preg material 816 passing between the driven rollers 812 a through812 g and the non-driven rollers 814 a through 814 g to be selectivelystretched in select sections. This embodiment allows the amount ofstretch-forming in the material to vary along the width and to varyalong the length of the material simultaneously, and to be programmedfor complex geometry parts requiring different degrees ofstretch-forming in different areas of the product. Driving individualsegmented rollers is accomplished with a number of different drivemeans. For example, separate individual motors could be used. In anotherexample, separate gear ratios connected to a common motor drive areused.

Referring to FIG. 9, a forming assembly 900 using pre-preg material 906that has a stretch-formed section 906 a is illustrated. In thisembodiment, the sheet of pre-preg material 906 will have anotherstretch-formed section (not shown) along an opposite edge (not shown) toaccommodate the forming surfaces 912, 914 and 916 of the tool 902. Aroll 908 of stretch-formed pre-preg material can be stored on a roll-off907, prior to use. The roll-off 907 is rotationally coupled to rollholder 910. An operator 904 aligns the material with the tool 902 toplace the pre-preg material 906 on the tool 902. Tool 902 rotates abouta central hub 930 that is rotationally coupled to a base 922. Aplacement device 920, places the pre-preg material 906 on formingsurfaces 912, 914, 916 of the tool 902. A forming head 918 presses thepre-preg material 906 onto the forming surfaces 912, 914, 916, of thetool 902, as the tool 902 rotates about the central hub 930. One benefitof the stretched sections 906 a of the pre-preg material 906 is when theoperator 904 aligns the material and starts placement of the pre-pregmaterial 906 on the forming surfaces 912, 914 and 916 of the tool 902,as the stretched edge sections 906 a allow the pre-preg material 906 tobe easily laid up on the forming surfaces 912, 914, 916. In particular,a mid-portion of the pre-preg material 906 will lay up on formingsurface 912, while sections near the edge of the pre-preg material 906,such as edge section 906 a, that are stretched will lay up on therespective flange forming surfaces 914 and 916 and will remain on theforming surfaces 914 and 916 until the forming head 918 presses thepre-preg material 906 onto the forming surfaces 912, 914, 916 of thetool 902. Without the stretching proximate the edge of the pre-pregmaterial 906, the pre-preg material 906 will tend to flip over on itselfproximate the edges of the pre-preg material 906. That is, withoutstretching the edges of the pre-preg material 906, the edges of thepre-preg material 906 will not initially conform to forming surfaces 914and 916 of the tool 902 and fold over onto itself on forming surface912. Also, the stretching of the edges, such as edge 906 a, of thepre-preg material 906 stretches the pre-preg material 906 to accommodatethe differences in radii on the flange forming surfaces 914 and 916.

FIG. 10 illustrates an implementation of a stretch-forming assembly 1000with the forming assembly 900, of an embodiment (e.g., FIG. 9). A rollof pre-preg material 1002 is stored on roll-off 1004, which isrotationally coupled to supply base 1008. The pre-preg material 1002, inthis embodiment, is passed through stretch-forming assembly 1000. Thestretch-formed pre-preg material 1006 then passes around guide roller1012, which directs the stretch-formed pre-preg material 1006 on thetool 902. The stretch-formed pre-preg material 1006 is then formed onthe tool 902, as described above in regard to FIG. 9. In the embodimentof FIG. 10, the guide roller 1012 includes conical ends 1011 that helpretain the form of the stretch-formed pre-preg material 1006 before itis applied to the tool 902.

FIG. 11A illustrates an embodiment of a stretch-forming assembly 1100, asupply roll-off 1130 and a storage core 1120. In this embodiment, thesupply roll-off 1130 includes a tension motor 1132 that supplies aselect amount of back tension to the supply pre-preg material 1102 toassist in the stretch-forming process and to keep the pre-preg material1102 aligned with the stretch-forming assembly 1100. Stretch-formedpre-preg material 1104 includes a non-stretched section 1104 b andstretched sections 1104 a and 1104 c. Although this example includes thenon-stretched section 1104 b positioned between the stretched sections1104 a and 1104 c, any desired arrangement and any number of stretchedand non-stretched sections can be used. In this embodiment, thestretch-formed pre-preg material 1104 is stored on the storage core1120. The storage core 1120 in this embodiment includes tapered endsections 1120 a and 1120 c and a mid-section 1120 b that correspond tothe respective sections 1104 a, 1104 b and 1104 c of the stretch-formedpre-preg material 1104. In particular, the tapered end sections 1120 aand 1120 c are used to retain the stretching in the stretch-formedpre-preg material 1104 when stored for a period of time. For example,roll-off 907 of FIG. 9 in one embodiment is the storage core 1120 ofFIG. 11A to retain the stretch-formed pre-preg material 1104 in thedesired stretch-formed shape. FIG. 11B illustrates a stretch-formingdevice of the stretch-forming assembly 1100 of FIG. 11A. Thestretch-forming device of this embodiment includes a pair of first niprollers 1140 and 1142 and a pair of secondary nip rollers 1148 and 1150that pass the pre-preg material 1102 and 1104. A pair of stretch-formingrollers 1144 and 1146 is positioned between the pair of first niprollers 1140 and 1142 and the pair of secondary nip rollers 1148 and1150. The pair of stretch-forming rollers 1144 and 1146 (mating rollers)each have end forming sections 1144 a, 1146 a, 1144 c and 1146 c (notvisible in FIG. 11B) that stretch-form select sections 1104 a and 1104 cof the pre-preg material 1102 into stretch-formed pre-preg material 1104as the pre-preg material 1102 passes between the stretch-forming rollers1144 and 1146. The secondary nip rollers 1148 and 1150 are of a selectlength so that they engage only the non stretch-formed section 1104 b ofthe stretch-formed pre-preg material 1104 as they pass thestretch-formed pre-preg material 1104. This prevents the secondary niprollers 1148 and 1150 from deteriorating the stretch-formed sections1104 a and 1104 c. In one embodiment, the pair of first nip rollers 1140and 1142, the constant diameter portion of the pair of second rollers1144 and 1146, and the pair of third nip rollers 1148 and 1150 aredriven at a synchronized speed. The stretch-formed re-preg material 1104is wound up on the shaped storage core 1120.

Referring to FIG. 12A, another embodiment of a stretch-forming device isillustrated. In this embodiment, the stretch-forming device is a shapedcore 1200 that can also be used to store the stretch-formed pre-pregmaterial. The embodiment of FIG. 12A illustrates a pair of nip rollers1220 and 1222 that provide back tension when applying the pre-pregmaterial to the shaped core 1200. As discussed above, the back tensionassists in the stretching and forming process and keeping the materialaligned with the stretch-forming device 1200. As illustrated in FIG.12A, the shaped core 1200 includes outer stretch-form sections 1200 aand 1200 c and a mid non-stretching section 1200 b. In an embodiment,the greatest diameter of the outer stretch-form sections 1200 a and 1200c is equal to the diameter the mid-non-stretching section 1200 b. Thisallows the flat pre-preg material to be aligned when it is rolled ontothe shaped core 1200. FIG. 12B illustrates another embodiment of astretch-forming device 1250 that uses a shaped core 1258 to formstretch-formed pre-preg material. In this embodiment, a tension motor1254 controls the distribution of pre-preg material 1252 to the shapedcore 1258. The shaped core 1258, in this embodiment, includes outerconical shaped stretch-forming sections 1258 a and 1258 c and a midnon-stretching section 1258 b. A nip roller 1260 is used to press amid-portion of the pre-preg material 1252 onto the mid non-stretchingsection 1258 b of the shaped core 1258. In operation, the shaped core1258 is rotated to draw the pre-preg material 1252 onto the shaped core1258. Tension motor 1254 keeps tension in the pre-preg material 1252 tohelp form the pre-preg material 1252 and maintain an alignment of thepre-preg material 1252 onto the surface sections of the shaped core1258. The nip roller 1260 keeps the mid-portion of the pre-preg material1252 in place while the outer portions of the pre-preg material 1252 arestretch-formed by the respective outer conical shaped stretch-formingsections 1258 a and 1258 b of the shaped core 1258. FIG. 13 illustrates,at least one layer of stretch-formed pre-preg material 1300 on theshaped core 1200. Hence, any number of layers of the pre-preg materialcan be placed on the shaped core 1200. The stretch-formed pre-pregmaterial 1300 includes outer shaped sections 1300 a and 1300 c and anon-stretched mid-section 1300 b. Various methods can be used tostretch-form the pre-preg material 1202 into outer stretch-form sections1200 a and 1200 c of the shaped core 1200. For example, the shaped core1200 with material 1202 could be subject to a vacuum bag, a vacuum bagand heat, or a vacuum bag with added external pressure. Other methodsinclude physical pressing devices (motion compaction mechanisms), suchas the transverse rollers 1400 a and 1400 b of FIG. 14. In thisembodiment, the transverse roller 1400 a and 1400 b press respectivesections of the pre-preg material 1202 in the valleys of the outerstretch-form sections 1200 a and 1200 c. The transverse rollers 1400 aand 1400 b move in a transverse direction in regard to the direction thepre-preg material 1202 is rolled onto the shaped core 1200.

Another example of a stretch-forming device using a physical pressingdevice is illustrated in FIG. 15. In this embodiment, a belt 1500 isused as a physical pressing device to stretch-form pre-preg material1520 on a shaped core 1200. The belt 1500 has outer press-formingsections 1500 a and 1500 c and a mid-section 1500 b that arecomplementary in shape to respective outer stretch-form sections 1200 aand 1200 c and the mid non-stretching section 1200 b of the shaped core1200. The outer press-forming sections 1500 a and 1500 c of the belt1500 press respective sections of the pre-preg material 1300 in thevalleys of the outer stretch-form sections 1200 a and 1200 c of theshaped core 1200 to form the stretch-formed pre-preg material 1300,which in this embodiment is wrapped around the shaped core 1200. Thebelt 1500, in this embodiment, is an endlessly looped belt that movesabout rotational idler rollers 1504 a, 1504 b and 1504 c. Idler roller1504 b controls a desired belt tension to keep the belt 1500 engagedintimately with the shaped core 1200 (or roller) and the appliedpre-preg material 1520. As discussed above, the stretch-formed pre-pregmaterial 1300 can then be stored on the shaped core 1200 until use. Hereagain, as with all embodiments, the placement and number of thestretch-form sections 1200 a and 1200 c of the shaped core 1200 and thecorresponding stretching sections 1500 a and 1500 c can be selected inany manner to achieve a desired outcome. Still another example of aphysical pressing device (motion compaction mechanism) is illustrated inFIG. 16. In this embodiment, a roller 1600 physical pressing device isused. The roller 1600 has outer press-forming sections 1600 a and 1600 cthat are complementary in shape to the outer stretch-forming sections1200 a and 1200 c of the shaped core 1200. In one embodiment, the outerstretch-forming sections 1200 a and 1200 c are a plurality of roundedteeth 220 (or shaped gear teeth) separated by a plurality of grooves.The outer press-forming sections 1600 a and 1600 c of the roller 1600press respective sections 1300 a and 1300 c of the pre-preg material1300 in the valleys of the outer stretch-form sections 1200 a and 1200 cto form the stretch-formed pre-preg material 1300. The roller 1600further has a center section 1600 b that is complementary in shape tocenter section 1200 b of the shaped core 1200. As a result, thestretch-formed pre-preg material 1300 is formed to have outer shapedsections 1300 a and 1300 c and a non-stretched mid-section 1300 b.

FIG. 17 illustrates a process flow diagram 1700 that can be used withthe shaped core 1200, as described above. As this process starts, one ormore layers of pre-preg material are initially rolled on the shaped core(1702). To stretch select sections of the pre-preg material about thesheet of pre-preg material's width, several methods can be use eitheralone, or in combination. The methods include physically pressing theselect sections of pre-preg material into stretching sections of theshaped core (1704), applying a vacuum (1706), applying heat (1708) andapplying atmospheric pressure (1710). As stated above, any single methodor any combination in any sequence can be used to form the pre-formed(or stretch-formed) pre-preg material (1712). For example, in oneembodiment only the physical pressing (1704) is used. In anotherembodiment, the pre-preg material is physically pressed (1704) and thenplaced in an autoclave that applies a vacuum (1706), heat (1708) andpressure (1710). Further, in another example embodiment physicalpressure (1704) and heat (1708) are applied to the one or more layers ofpre-preg material on the shaped core (1702) separately. The shaped coreis then vacuumed bagged and pressure (1710) and vacuum (1706) areapplied to form the pre-formed pre-preg material (1712). In stillanother example embodiment, physical pressure (1704) and a vacuum (1706)are first applied. Then, heat (1708) and pressure (1710) are applied toform the pre-formed pre-preg material (1712). Hence, as stated above,any single method or any combination of methods in any sequencediscussed above can be used to form the pre-formed pre-preg material onthe shaped core.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement, which is calculated to achieve the same purpose,may be substituted for the specific embodiments shown. This applicationis intended to cover any adaptations or variations of the presentdisclosure. Therefore, it is manifestly intended that this disclosure belimited only by the claims and the equivalents thereof.

What is claimed is:
 1. A system for selectively stretch-forming a sheet of pre-preg material, the system comprising: a drive assembly comprising at least one motor; the sheet of pre-preg material; a roller comprising a plurality of forming segments, the plurality of forming segments positioned along and intersecting a common axis of rotation, the plurality of forming segments comprising: a first forming segment; and a second forming segment positioned adjacent the first forming segment along the common axis of rotation; and an opposing roller; wherein the system is configured to pass the sheet of pre-preg material between the roller and the opposing roller; wherein the at least one motor is configured to drive the first forming segment at a first rotational speed; wherein the drive assembly is configured to drive the second forming segment independently of the first forming segment at a second rotational speed that is different than the first rotational speed; and wherein the first forming segment and the second forming segment are configured to selectively stretch-form at least one section along at least one of a width or a length of the sheet of pre-preg material in relation to at least one other adjacent section along at least one of the width or the length of the sheet of pre-preg material as the sheet of pre-preg material passes between the roller and the opposing roller.
 2. The system of claim 1, wherein the opposing roller comprises a plurality of forming segments.
 3. The system of claim 2, wherein the plurality of forming segments of the opposing roller is non-driven.
 4. The system of claim 2, wherein the plurality of forming segments of the opposing roller is arranged to mate with the plurality of forming segments of the roller so as to form pairs of mating forming segments.
 5. The system of claim 4, wherein the plurality of forming segments of the roller further comprises at least a third forming segment.
 6. The system of claim 5, wherein the forming segments of at least one pair of mating forming segments are conical in shape.
 7. The system of claim 5, wherein the forming segments of at least one pair of mating forming segments include shaped gear teeth.
 8. The system of claim 5, wherein the plurality of forming segments of the opposing roller comprises at least three forming segments.
 9. The system apparatus of claim 1, further comprising a tension device configured and arranged to tension the at least one section of the sheet of pre-preg material as the sheet of pre-preg material passes between the roller and the opposing roller.
 10. The system of claim 1, further comprising a storage core having a width, the storage core having at least one section along the width configured to maintain the at least one section of the sheet of pre-preg material in a stretch-formed state relative to another section of the sheet of pre-preg material on the storage core.
 11. The system of claim 1, further comprising a shaped core having a core width, the shaped core having at least one stretch-forming section along the core width that is different than at least one other adjacent section along the core width, the at least one stretch-forming section configured to stretch-form the at least one section of the sheet of pre-preg material.
 12. The system of claim 11, further comprising at least one transverse motion compaction mechanism selectively engaging the at least one stretch-forming section of the shaped core to at least partially stretch-form the at least one section of the sheet of pre-preg material.
 13. The system of claim 11, further comprising a shaped belt assembly including at least one press forming section configured to engage the at least one stretch-forming section of the shaped core to at least partially stretch-form the at least one section of the sheet of pre-preg material.
 14. The system of claim 11, further comprising a roller including at least one press forming section configured to engage the at least one stretch-forming section of the shaped core to help stretch-form the at least one section of the sheet of pre-preg material.
 15. The system of claim 4, further comprising a back tension device configured to apply tension to the sheet of pre-preg material in a direction opposite to a direction of intended travel of the sheet of pre-preg material through the system.
 16. The system of claim 15, wherein the back tension device comprises at least one of a supply roll-off or a set of nip rollers.
 17. The system of claim 1, wherein the roller and the opposing roller are configured to dispense the at least one section of the sheet of pre-prep material in a stretch-formed state before the sheet of pre-prep material is applied to a forming surface of a forming tool that is used to shape the sheet of pre-prep material into a shape of a desired composite part.
 18. The system of claim 4, wherein at least one forming segment of the plurality of forming segments of the roller and at least one forming segment of the plurality of forming segments of the opposing roller are configured to be driven at substantially the same rotational speed by the at least one motor.
 19. The system of claim 1, wherein the roller and the opposing roller are configured to apply a stretch-forming force to the at least one section of the sheet of pre-prep material as the sheet of pre-preg material passes between the roller and the opposing roller.
 20. The system of claim 5, wherein the plurality of forming segments of the roller is configured to be independently driven with the drive assembly.
 21. The system of claim 1, wherein the at least one motor comprises a plurality of motors, each motor of the plurality of motors being configured to drive one forming segment of the plurality of forming segments.
 22. The system of claim 1, wherein the drive assembly further comprises a belt driven by the at least one motor.
 23. The system of claim 1, further comprising a back tension device configured to apply tension to the sheet of pre-preg material in a direction opposite to a direction of intended travel of the sheet of pre-preg material through the system apparatus. 